1. Field of the Invention
The present invention relates to a transparent conductive film having a polymer film and a transparent conductive layer provided thereon, especially a transparent conductive film improved in durability and mechanical and electrical properties, a process for the preparation thereof, and a touch panel provided with the transparent conductive film, as well as transparent conductive plate and the process for the preparation thereof.
2. Description of the Related Art
A touch panel according to resistance sensitive system, in which signals are input by pushing a panel with a fingertip or pen and bringing the panel in contact with an opposite electrode to turn on electricity, is advantageous to enable reduction of the size, weight or thickness. Therefore, the touch panel is widely used in input equipments of various home appliances and portable terminals.
The touch panel according to resistance sensitive system has a structure that an upper electrode comprising a polymer base film, an undercoat layer and a transparent conductive layer superposed in this order is laminated on a lower electrode comprising a plastic or glass thick plate and a transparent electrode formed thereon through spacers, such that the transparent conductive layer and transparent electrode face each other. When a display surface of the upper electrode is pushed with a fingertip or pen, the surface comes in contact with an opposite electrode to turn on electricity. Generally, a hard coat layer is formed on the display surface of the upper electrode to protect the polymer base film.
The undercoat layer is generally provided to improve bonding strength between the polymer (base) film and transparent conductive layer and prevent peeling of the transparent conductive layer caused by repetition of the pushing.
As the transparent conductive layer usable in the touch panel, for example, JA60-131711 describes a transparent conductive layer subjected to an annealing treatment to improve mechanical and chemical properties, the layer being provided on an undercoat layer of organic silicon compound. JA02-66809 describes a composite of a substrate, an adhesive layer, a substrate and a transparent conductive layer, in which the adhesive layer serves to relax the stress applied to the transparent conductive layer.